The present invention relates to a system of independently moving elements with characteristics which make them bind reversibly to each other according to certain rules such that they form self-replicating and mutating polymers subject to the general principles of natural selection, and use of the system to simulate the origin of life and molecular evolution.
Self-replication and adaptability are the hallmarks of what is recognize as living systems, and in all biological systems both these properties are directly related to the structure and function of nucleic acids, i.e. DNA and RNA.
DNA is a linear polymer of deoxyribonucleotides. Each deoxyribonucleotide consists of three main groups, 1) a deoxyribose-a pentose sugar, 2) a phosphate group and 3) one of the heterocyclic nitrogenous bases, adenine (A), thymine (T), guanine (G) or cytosine (C)
A double helical DNA molecule consists of two complimentary, antiparallel strands of DNA. The phosphodiester bonds linking the 5xe2x80x2 and 3xe2x80x2 carbons of the adjacent sugar residues results in directionality of the polynucleotide chain. In the double stranded DNA molecule, the phosphodiester bonds of each polynucleotide chain run in opposite directions (i.e., 5xe2x80x2-3xe2x80x2 and 3xe2x80x2-5xe2x80x2) and are thus said to be antiparallel. Base pairing between strands is the result of hydrogen bonding between adjacent base pairs. Normally, A residues form 2 hydrogen bonds with T, and G residues form 3 hydrogen bonds with C resulting in complementary base pairing between the DNA strands. Therefore the sequence of bases in one strand determines the sequence of the complementary strand and is the basis of DNA replication. The two strands of DNA coil around a central axis in a right handed manner with the sugar-phosphate backbone on the exterior and the bases on the interior. The aromatic rings of the bases are stacked in the middle, perpendicular to the axis of the DNA double helix. A full rotation in the helical structure comprises ten nucleotides.
The nucleotides in a DNA strand are held together by strong covalent bonds between the phosphate and the sugar residues. The creation and breaking of these bonds requires supply of energy and in present organisms these reactions are catalyzed by energy consuming enzymatic reactions. The bonds between the complementary bases are weak hydrogen bonds and the attractive forces between two single nucleotides are weak. When the nucleotides are organized in DNA strands, large numbers of hydrogen bonds are coordinated, so that the attractive forces between two complementary strands become relatively strong. They are however responsive to heat (below 100xc2x0 C.) and alkali, and are considerably weaker than the covalent bonds composing in the individual DNA strands.
All biological systems are based on the ability of the DNA molecule to store and reproduce information. The genetic information is stored in the structure of the DNA molecule as different sequences of nucleotides. Reproducing this information is achieved in that an existing nucleotide chain, via an intricate network of biochemical reactions, catalyzes the creation of a complementary chain.
It is today widely accepted that life on earth evolved from simple molecular structures by means of natural selection. This evolution process, which was first recognized by Charles R. Darwin, explains biological evolution in terms of a simple mechanism directly related to self-replication of biological information.
Human civilization is at present experiencing the early signs of a fast approaching revolution driven by incredible advances in biotechnology. Cloning of mammals is today a reality and genetic manipulation is performed as routine assays in laboratories all over the world. These advances constitute complex challenges to different parts of society, including political as well as private decision making. Consequently, there is a growing need for easily accessible information related to the fundamental aspects of biology. This need can be meet by a system, which in a simple manner simulates the biochemical and evolutionary mechanisms underlying the phenomenon commonly recognized as life.
Different systems have been proposed to simulate self-replication. In American Scientist, Vol. 47; 261-263, 1959 (H. J. Morowitz) it is suggested a system for simulating replication based on two types of element A and B, floating in water. A and B can bind to each other, but only if the binding is initiated by an existing complex of A and B. Thus an AB unit can catalyze creation of a new AB unit. Each element carries a battery and an electromagnet, but are also suggested to be powered by  less than  less than solar batteries greater than  greater than . The described elements can, however, only combine to form AB units, and the system cannot proceed further to form more complex structures like polymers. Consequently this system can neither generate mutations, nor simulate evolution by means of natural selection. Furthermore, the binding between A and B elements is not reversible so there is no possibility of re-circulation (death) of the elements such that the process is open-ended. This system does not involve the use of natural magnets and ferromagnetism, nor is it any obvious manner by which such material could be used.
There are a number of known systems for demonstrating molecule structures such as proteins, DNA, or RNA wherein the elements are held together by magnetic forces, glue etc. (DE 23 41 320 A1, SE 15 58 07, U.S. Pat. No. 3,594,924). These systems are, however, all static models, which in no way simulate reversible chemical interactions, self-replication or evolutionary processes.
In SU 89 66 75 B it is described magnetic elements simulating items for demonstration of physico-mechanical properties of solids. The magnet elements are enclosed in an elastic shell and floating in a tank filled with a liquid. The repulsion forces between items can now be simulated in addition to elastic properties of solids. This system does not simulate self-replication or evolutionary processes, nor is it suggested to do so.
Thus there is an object to provide a system for demonstration/simulation of open-ended self-replication of polymers and the principle of evolution by means of natural selection.
These objects are obtained by the present invention characterized by the enclosed claims.
The present invention provides a system of independently moving elements with characteristics which make them bind to each other according to certain rules such that they form self-replicating and mutating polymers subject to the general principles of natural selection, and use of the system to simulate the origin of life and molecular evolution. The invention further comprises use of the system to simulate self-replication and natural selection of nucleic acids, wherein the evolution process is promoted and manipulated by controllable changes in the environment of the elements, e.g. temperature, light and turbulence, and by introducing modifying elements, and use of the system as an educational tool, an interactive game, a decoration and a tool for scientific purposes and computational purposes.